Totally, TOTALLY frustrated - Air compressor issue.

[luvrbus]

Those compressors have a port on each side to mount a governor I cannot tell because of the water line if the front is plugged or not

good luck

[Chaz]

I just got done talking with BK a little while ago. He is correct with what he said except it only takes about 3 (three) seconds or so to blow my finger off. 

Zub - Hydrolocked, huh? Hmmmm....... I guess if that is a possibility, I can air it up via shop air and try to blow it. As Dallas mentioned, I need to purge the lines and tanks of crud. That system has been neglected for quite awhile before me.

If it's suspected that the governor is unloading the compressor partially, or early, then a performance test could be run with the governor removed from the pump. Of course there will be no unloading, so the engine should be stopped before dangerously high pressures  are reached. Pressure rise of course will be no faster than if the governor would be in place, so there's no danger of sudden pressure spike.

My guess is that the pressure would come up like a "good system" should, say, 3-5 minutes maybe?? Mine took 14 minutes.

The plug was just a piece of cardboard held over the ports with plastic inserts in the bolt holes. (they aren't plugged)

The discharge hose is 1/2" Weatherhead Air Brake hose. Not hydraulic line as we initially thought. Is 1/2" too small??

Since I cleaned the gov. it now has a leak around the big "C" ring opening where the guts come out. Looks like I need a new one now.

After the batteries charge awhile, I'll give her another go. My guess is, the same result as I really haven't done anything that seems to be "the fix" I was looking for. I'll post after I try it to let ya know , otherwise, I'll get a new gov. and then retry it. I will then probably come "begging" yet again. 

I have drained my tanks a couple times. I'm not sure which one the "wet tank" is or where. And that goes for the "skinner valves" as well. But I do think I will be bothering Dallas or at least someone on how to slick up the system. I know it needs it!!!
Thanx again guys.................
  Chaz

[luvrbus]

The one between the 2 bolt holes on the front has to have a 1/4 inch pipe plug

good luck

[TedsBUSted]

Y'all are all correct in the areas you mention. BUT the problem is the COMPRESSOR is not sucking in or putting out hardly any air!

He  took off the discharge line and held his finger over the outlet and it hardly blew his finger off it and took like 3o seconds or so to build enough pressure to do that.

So checking lines, cracking fittings, and cleaning lines and tanks is not going to solve the problem until he gets air pressure out of the compressor first. . . .

I guess I missed the finger-test description. Regardless, if the governor is unloading the compressor, there will be no air flow pumped through the compressor. So unless the compressor is tested while isolated from the system and governor, the "no air flow" condition doesn't necessarily indicate a compressor problem.

Ted

[Busted Knuckle]

Chaz after reading responses and thinking 2 things come to mind.

One go ahead and turn the adjustment screw on the governor counter clockwise one full turn. (It can't hurt, & might help.)

Two try taking the return line (signal line, return line, what ever you want to call it, but the 1/4 line coming into the governor from the air system)  lose from the governor. It could be plugged up and causing the problem. (I kinda doubt it and still lean toward the governor itself especially missing the cap & O-ring)

The wet tank will be the first tank in the system from the compressor and like I said b4 I don't know much about GM's except they put the motor in funny!
 BK  

[azdieselman]

What is under your intake pipe? Do you have a reed valve? Check the intake poppet valves, maybe 1 has a broken spring. What is the part number of the compressor you have?

[Bill B /bus]

Chaz

Your wet/dry tank is located in the fuel tank compartment. The drain valves are quarter turn ball valves located on the after bulkhead towards the outside skin. Remember GM valves are backwards., inline is closed.. You might `even pull the lines at the tank bottom.

Can't wait to read the rest of the saga - the previous owner did it in the system with dirt. Stolen from  CLUE without permission.

Good luck
Bill

[Chaz]

No good.         
After 4 minutes I had a grand total of about 20 psi. The Gov. is leaking bad.
My next move will be getting a gov and seeing what that does.
Then the next will be blowing the tank (s). What tank is in the AC bay on the passenger side?? I don't recall the one in the fuel bay as the fuel tank takes the whole thing up. There is also one under the driver that I purge as well.
Thanx a million guys!!!!!!!!!!!!!!!
We'll see what tommorrow brings. (enough disappointment for one day) 

Chaz

[h1deout96a3]

has anybody checked the drive gears, the 2 piece drive gear will slip in itself. i have seen this a lot, will cause slow air build up,also hard to find.make sure driven gear is solid steel. whats the all rebult compressors are bad?

[eagle19952]

do you have an Air Dryer.....it will be the first MAJOR point of restriction.

A compressor operates continuously until it is told to stop.
The Governor is told by the signal line that the tanks have reached the set gov pressure.
In the air tank filling portion of the compressors job the movement of the pistons are essentially all that is in play.
The piston down stroke pulls air past the unload-er into the cylinder while also holding the discharge valves on their seats.
When the tanks send a pressure signal to the gov. the air pressure then tells the unload-er to not allow air to pass the intake valves (basically).
This then causes the two piston to push air back and forth from one cylinder to the other until the system pressure drops and relieves the pressure on the unload-er valve and allows the compressor to recycle the process over.
I would check or bypass my air dryer...alot will disagree BUT air dryers are for places where air lines can freeze or for people who don't drain their tanks DAILY or more.

The two "bolt" looking things on top of the compressor are the discharge valve "holders".....I< as in me< would get a BIG breaker bar and open them up, the discharge valves are nothing more than a thin square piece of metal.Take a magnet stick and take them out,if they are new they will not have a circle (about the size of a nickel) worn into it's face. IF you find that this circle is prominent on both sides,you have bought a paint job.<some rebuilders simply flip the valves over>
If it is ( a worn circle)on one side and you can "catch" a finger nail, it is probably not seating and this may indicate that your compressor is thinking it is in the unload-er cycle...in other words your compressor cylinders are primarily "swapping" air and not discharging it to your tanks at the CFM of your unit capability.
A human finger would be hard pressed to withhold/contain 2psi.
My bet is the air dryer or the discharge valves or discharge valve springs.
If it were the piston rings it might never get to 120-130 psi.
In the arctic (Alaska) we used cases of fuel deicer to flush oily air tanks...simply by filling the air line down stream of the dryer and the draining the air tanks, simply leaving the tank drain open over nite will let gravity drain any oily/water mix out of your tanks.
If you do this without pumping your brakes none of this deicer will get to your brake diaphragms.

We used HEET.

This may not help but was free and may give you something to scratch your itch with.....
And I am sure someone will tell me where I am wrong, but I understand me....
So CHECK OUT THE LINK>>Get some coffee.

http://docs.google.com/viewer?a=v&q=cache:CSoawqvXRJoJ:www.bendixvrc.com/itemDisplay.asp?documentID%3D2383+bendix+tu+flo+500+troubleshooting&hl=en&gl=us&pid=bl&srcid=ADGEESiiU4AI8HbicY758-laCshjWFRySryloaurnjYP-wPJEVPTzcPEQLUJ2xKNSMFWgyB5meqye1EhsP1lceSzofijcFrP6i7Ii91AGgZPl-O1UdoBhRWhVqKsyEg2GIkhZ6IvhsqK&sig=AHIEtbRD-UP0wl2WTpByc39lA1CWWfR_7g&pli=1

[eagle19952]

Get some more coffee,
http://www.beamalarm.com/Documents/haldex_d2_governor_service_data.htm

[bevans6]

One thing I noticed is that he said his discharge line from the compressor to the bus is only a 1/2" line.  I don't know the exact size but mine is closer to an inch. 

Brian

[luvrbus]

Hopefully he will figure it out this what you get with a retort by the PO he is no where close to a OEM,the OEM compressors on that bus don't even have unloader valves you can work on from the top and they do have a 1/2 line coming from the center of the head so his line is OEM and is the right size but wrong type


good luck

[TomC]

All the governor does is regulate the on/off of the compressor-not the amount it pumps. If it is pumping and cutting out at around 120psi, then coming back on around 90psi, then the governor is working.  The slowness of your compressor maybe caused by you mistakenly getting a turbocharged compressor.  The turbocharged compressors have lower compression ratios (just like a turbocharged engine) and initially pump up very slowly.  But when you're on the road and pulling a hill with full turbocharging pressure (the air compressor air feed line is on the pressure side of the air intake), the air pressure goes up very quickly from 90-120psi-like only taking about 20 seconds to refill.
Since you don't have a turbocharged engine, I would suggest taking it back and having a new one installed.  Sometimes things like this happen.  
On my Mercedes 300 turbodiesel, we went through 3 Bosch factory rebuilt starters before we found one that worked right (and that's taking it on and off the car everytime-luckily it was my mechanic and not me).  Good Luck, TomC

[eagle19952]

Time for another pot of coffee...
http://www.tamesisriver.com.ar/PDF/Compresores%20Bendix%20Tu-Flo.pdf

http://www.bendixvrc.com/

I think (and am trying to find) that DOT reg and proper installation of a compressor discharge line  should never go "up" but always down and that for safety (heat/fire) related reasons the first pieceshould be Velvac or copper....
http://www.easternmarine.com/24-Air-Compressor-Discharge-Hose-142524-0/